Adjustable fluidic lenses for correcting piston/defocus/astigmatism aberrations induced by MEMS deformable mirrors

An adjustable fluidic lens is typically utilizing curvature change and is promising to correct the aberrations such as piston, defocus, and astigmatism. In this article, capability of adjustable fluidic lenses to correct the induced wavefront aberrations is investigated systematically, with particular attention placed on interpretation of Zernike modes and exploration of the potentials of fluidic lenses. In addition, aberrations are expressed in Zernike polynomials and the first six modes commonly encountered in ophthalmology are carefully examined. Three different wavefront aberrations are intentionally induced by a commercial micro-electrical-mechanical systems (MEMS) deformable mirrors (DM) with 140 actuators. The optical properties of fluidic lenses corrections are characterized by Shack-Hartmann measurements. Experimental results show that piston mode (Z ₁) can be significantly improved from 0.972 to -0.031 μm using fluidic lenses by injecting DI water as little as 0.02 ml (resultant meniscus curvature is 392.8 mm). Similar improvements can be found in defocus (Z ₅)/astigmatism (Z ₆) and aberrations are reduced for both modes from -0.15 μm/-0.48 μm to 0.02 μm/0.085 μm, respectively. When injected volume of 0.1 ml (resultant meniscus curvature is 78.9 mm), we can experimentally deduce that aberrations of Z ₃/Z ₅ induced by MEMS DM at a magnitude of 0.486 μm/-1.472 μm, fluidic lenses can only marginally improved to -0.245 μm/0.305 μm.